Bug detector

ABSTRACT

This present invention provides a bug detector for detecting a hidden bug, comprising: an acoustic generator, an identification decoder, and a control device. The acoustic generator generates a specific audio signal for the microphone of the bug receiving the specific audio signal and outputting a radio signal through the radio transmitter. The identification decoder receives the radio signal for decoding so as to obtain a decoded audio signal. The control device connects to the acoustic generator and the identification decoder for comparing the specific audio signal with the decoded audio signal so as to determine that the bug is existence or not.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a bug detector and, more particularly, to abug detector for correctly determining whether a bug is existence ornot.

2. Description of Related Art

A bug usually was hidden in a room for stealing some confidentialinformation in some espionage activity. The bug can receive an audiosignal to perform modulation with a carrier wave for converting theaudio signal in a radio frequency signal form. Therefore, a receiverlocating at somewhere receives the radio frequency signal.

Generally, the bug is in small size to be easily hidden. Hence, it isobviously impracticable to detect the location of the bug by actuallysearching. FIG. 1 illustrates a schematic view of a conventional bugdetector. Referring to FIG. 1, the audio receiver 1 as a bug detectorcan search a radio frequency signal outputted by the bug 2 fordetermining whether the bug 2 is existence or not. The abovementionedmethod needs someone to generate some sound so as to drive the bug 2 tooutput the radio frequency signal; however, which is very inconvenientfor the users. In addition, the audio receiver 1 may receive somewireless waves such as other radio frequency waves or undesired sound ornoise. Therefore, the audio receiver 1 can not correctly determinewhether the bug is existence or not. Therefore, it is desirable toprovide a bug detector to mitigate and/or obviate the aforementionedproblems.

SUMMARY OF THE INVENTION

This present invention provides a bug detector for detecting a hiddenbug, comprising: an acoustic generator generating a specific audiosignal for a microphone of the bug receiving the specific audio signaland a radio transmitter outputting a corresponding radio signal; anidentification decoder receiving the radio signal for decoding so as toobtain a decoded audio signal; and a control device connectingrespectively to the acoustic generator and the identification decoderfor controlling the acoustic generator to generating the specific audiosignal, and determining that if the specific audio signal corresponds tothe decoded audio signal generated by the identification decoder so asto determine that the bug is existence or not.

The control device comprises a display and switch input unit comprisinga plurality of switches for setting different on/off status forcontrolling the operation mode of the bug detector and a plurality oflight emitting diodes with different display status capable ofdisplaying different operation status of the bug detector, and a centralprocessor coupled to the acoustic generator, the display and switchinput unit, and the identification decoder for providing the functionsof controlling the audio outputting, display and input switching, andreceiving and data inputting.

The central processor operates the switches to generate an audioencoding signal to be transmitted to the acoustic generator, a volumecontrol signal to be transmitted to the acoustic generator, and afrequency switching signal to be transmitted to the identificationdecoder.

The acoustic generator comprises an audio signal generator, an audioamplifier, and a speaker. The audio signal generator connects to thecentral processor for receiving the audio encoding signal so as togenerate the specific audio signal; the audio amplifier connects to theaudio signal generator and the central processor respectively,comprising a gain controller for receiving the volume control signal toamplify the specific audio signal generated by the audio signalgenerator; the speaker electrically connects to the audio amplifier foroutputting a audio corresponding to the specific audio signal.

The identification decoder comprises a broadband wireless receiver, andan audio decoder. The broadband wireless receiver connects to thecentral processor for receiving the frequency switching signal to switchat least one receiving frequency for receiving the radio signal; theaudio decoder connects to the broadband wireless receiver and thecentral processor respectively for receiving the radio signal to decodeso as to obtain the decoded audio signal and transmit the decoded audiosignal to the central processor.

The central processor determines that whether the decoded audio signalis corresponding to the audio encoding signal or not; if true, then thecentral processor controls active quantity or brightness of the lightemitting diodes according to the intensity of the radio signal.

Therefore, compared with those in the prior art, this present inventionprovides a bug detector with a further means for identifying a specificaudio signal. The user only needs to use the acoustic generator togenerate the specific audio signal rather than making some sound. Thebug will generate a corresponding radio signal after receiving thespecific audio signal. Then, the identification decoder receives theradio signal for decoding so as to generate a decoded audio signal.Finally, the control device compares the specific audio signal with thedecoded audio signal to determine if the decoded audio signalcorresponds to the specific audio signal so as to prevent fromdetermining wrong due to ordinary noise. Therefore, the accuracy of thedetermination of the bug existence is improved.

Other objects, advantages, and novel features of the invention willbecome more apparent from the following detailed description when takenin conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a schematic view of conventional bug detector.

FIG. 2 shows a schematic view illustrating a bug detector according to apreferred embodiment of the present invention.

FIG. 3 shows a diagram illustrating a control device according to apreferred embodiment of the present invention.

FIG. 4 shows a diagram illustrating an acoustic generator according to apreferred embodiment of the present invention.

FIG. 5 shows a diagram illustrating an identification decoder accordingto a preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 2 shows a schematic view illustrating a bug detector according to apreferred embodiment of the present invention.

As shown in FIG. 2, the present invention provides a bug detector fordetecting a hidden bug 24 comprising an acoustic generator 21, aidentification decoder 22, and a control device 23. The acousticgenerator 21 generates a specific audio signal, received by themicrophone 241 of the bug 24, and then a radio transmitter (not shown)will output a corresponding radio signal to the specific audio signal.The identification decoder 22 receives the radio signal for decoding soas to generate a decoded audio signal. The control device 23 connects tothe acoustic generator 21 and the identification decoder 22 respectivelyfor controlling the acoustic generator 21 to generate the specific audiosignal, and determining that if the decoded audio signal generated bythe identification decoder 22 is corresponding to the specific audiosignal so as to determine if the bug 24 is existence or not. The controldevice 23 comprises a central processor 231, and a display and switchinput unit 232. The central processor 231 couples to the acousticgenerator 21, the display and switch input unit 232 and theidentification decoder 22 respectively for providing the functions ofcontrolling the audio outputting, display and input switching, andreceiving and data inputting. As shown in FIG. 3, the display and switchinput unit 232 comprises a plurality of switches 2321 and a plurality oflight emitting diodes 2322. The switches 2321 are provided settingdifferent on/off status for the central processor 231 to read and thenthe central processor 231 controls the operation mode of the bugdetector. The light emitting diodes 2322 are provided for displayingdifferent display status capable of displaying different operationstatus of the bug detector. Therefore, the central processor 231 cantransmit an audio encoding signal to the acoustic generator 21 accordingto the different status set by the switches 2321 for determining thefrequency of the specific audio signal, a volume control signal to theacoustic generator 21 for controlling the volume of the specific audiosignal, and a frequency switching signal to the identification decoder22 for switching the receiving frequency, wherein all of the audioencoding signal, the volume control signal, and the frequency switchingsignal are 4-bit signals.

Referring to FIG. 4, which shows the block diagram of the acousticgenerator 21 according to the present invention. The acoustic generator21 comprises an audio signal generator 211, an audio amplifier 212, anda speaker 213. The audio signal generator 211 connects to the centralprocessor 231 through the pins D0, D1, D2, and D3 for receiving theaudio encoding signal so as to generate the specific audio signalaccording to the audio encoding signal. The audio amplifier 212comprises a gain controller 2121 for controlling the amplified multiplevalue. The gain controller 2121 has the pins G0, G1, G2, and G3receiving the volume control signal transmitted by the central processor231 for controlling the amplified multiple value. The audio amplifier212 connects to the audio signal generator 211 for amplifying thereceived specific sound signal. The speaker 213 electrically connects tothe audio amplifier 212 for outputting a corresponding audio accordingto the amplified specific audio signal as mentioned above.

As shown in FIG. 5, which shows the circuit scheme of the identificationdecoder 22 of the present invention, the identification decoder 22comprises a broadband wireless receiver 221 and an audio decoder 222.

The above-mentioned broadband wireless receiver 221 connects to thecentral processor 231 and the audio decoder 222 respectively. Thebroadband wireless receiver 221 comprises an antenna 2211, a low noiseamplifier 2212 connected to the antenna 2211, a mixer 2213 connected tothe low noise amplifier 2212, a voltage-controlled oscillator 2214connected to the mixer 2213, a middle-frequency amplifier 2215 connectedto the mixer 2213, and a filter 2216 connected to the middle-frequencyamplifier 2215 and the audio decoder 222 respectively. Thevoltage-controlled oscillator 2214 has four pins V0, V1, V2, and V3 forreceiving the frequency switching signal transmitted by the centralprocessor 231 to generate at least one local oscillating frequencyaccording to the frequency switching signal. The mixer 2213 descends thefrequency of the radio signal to at least one middle-frequency signalwith the at least one local oscillating frequency. Therefore, asmentioned above, the broadband wireless receiver 221 scans the radiosignal according to the frequency switching signal. The radio signal isreceived with the antenna 2211, amplified and transmitted to the mixer2213 with the low noise amplifier 2212. The mixer 2213 receives at leastone local oscillating frequency sent out by the voltage-controlledoscillator 2214 for converting the radio signal to a middle-frequencysignal. The middle-frequency amplifier 2215 amplified the mid-frequencysignal, and then the filter 2216 will filter out noise of themiddle-frequency signal so as to transmit to the audio decoder 222.

The audio decoder 222 comprises a frequency/audio detector 2221 and adecoder 2222, wherein the frequency/audio detector 2221 connects to thefilter 2216 and the decoder 2222 respectively. The decoder 2222 connectsto the central processor 231 through the pins d0, d1, d2, and d3. Thefrequency/audio detector 2221 receives the descended middle-frequencyradio signal for performing demodulation so as to generate an audiosignal. After that, the audio signal is transmitted to the decoder 2222for decoding and then obtaining a 4-bit decoded audio signal. Thefrequency/audio detector 2221 transmits the 4-bit decoded audio signalto the central processor 231 through the pins d0, d1, d2, and d3. Thecentral processor 231 determines that whether the 4-bit decoded audiosignal is corresponding to the audio encoding signal or not; if true,then the central processor 231 can determine that the generated specificaudio signal indeed received by a bug and the bug sends out acorresponding radio signal. Therefore, the existence of the bug isconfirmed. Further, the central processor 231 also can control activequantity or brightness of the plurality of light emitting diodes 2322according to the received intensity of the radio signal.

When using, user can operate the plurality of switches 2321 first fordriving the central processor 231 to generate an audio encoding signalto transmit to the audio signal generator 211 for generating thespecific audio signal. And then, amplifying the volume control signaltransmitted to the audio amplifier 212 for amplifying the specific audiosignal. After that, enabling the speaker 213 to send out voicecontinuously to detect in a broad range.

If a hidden bug 24 indeed exists in somewhere, the identificationdecoder 22 can obtain the specific audio signal and the control device23 can control the lighting of the light emitting diodes 2322 toindicate the existence of the bug 24. For identifying the real locationof the bug 24, the user can lower the volume control signal fordecreasing the intensity of the radio signal and move the bug detector.While the intensity of the radio signal becomes strong again, the usercan lower the volume control signal for decreasing the strength theradio signal and move the bug detector again. After repeating theabove-mentioned step, the position of the bug 24 can be allocated by thebug detector.

From the above-mentioned, this present invention provides a bug detectorwith a means for identifying a specific audio signal. The user onlyneeds to use the acoustic generator to generate a specific audio signalwithout make any sound, and the bug will generate a radio signal afterreceiving the specific audio signal. The identification decoder receivesthe radio signal for decoding so as to generate a decoded audio signal.Thus, the control device compares the specific audio signal with thedecoded audio signal to check if the decoded audio signal iscorresponding to the specific audio signal so as to determine the bug isexistence or not.

Although the present invention has been explained in relation to itspreferred embodiment, it is to be understood that many other possiblemodifications and variations can be made without departing from thescope of the invention as hereinafter claimed.

1. A bug detector for detecting a hidden bug, comprising: an acousticgenerator, generating a specific audio signal for a microphone of thebug receiving the specific audio signal and a radio transmitter of thebug outputting a corresponding radio signal; an identification decoder,receiving the radio signal for decoding so as to obtain a decoded audiosignal; and a control device, connecting respectively to the acousticgenerator and the identification decoder for controlling the acousticgenerator to generating the specific audio signal, and determining thatif the specific audio signal corresponds to the decoded audio signalgenerated by the identification decoder so as to determine that the bugis existence or not.
 2. The bug detector as claimed in claim 1, whereinthe control device comprising: a display and switch input unit,comprising a plurality of switches for setting different on/off statusfor controlling the operation mode of the bug detector and a pluralityof light emitting diodes with different display status capable ofdisplaying different operation status of the bug detector; and a centralprocessor, coupled to the acoustic generator, the display and switchinput unit, and the identification decoder for providing the functionsof controlling the audio outputting, display and input switching, andreceiving and data inputting.
 3. The bug detector as claimed in claim 2,wherein the central processor operates the switches to generate an audioencoding signal to be transmitted to the acoustic generator, a volumecontrol signal to be transmitted to the acoustic generator, and afrequency switching signal to be transmitted to the identificationdecoder.
 4. The bug detector as claimed in claim 2, wherein the acousticgenerator comprises an audio signal generator, an audio amplifier, and aspeaker.
 5. The bug detector as claimed in claim 4, wherein the audiosignal generator connects to the central processor for receiving theaudio encoding signal so as to generate the specific audio signal; theaudio amplifier connects to the audio signal generator and the centralprocessor respectively, comprising a gain controller for receiving thevolume control signal to amplify the specific audio signal generated bythe audio signal generator; the speaker electrically connects to theaudio amplifier for outputting a audio corresponding to the specificaudio signal.
 6. The bug detector as claimed in claim 5, wherein theidentification decoder comprises a broadband wireless receiver, and anaudio decoder.
 7. The bug detector as claimed in claim 6, wherein thebroadband wireless receiver connects to the central processor forreceiving the frequency switching signal to switch at least onereceiving frequency for receiving the radio signal; the audio decoderconnects to the broadband wireless receiver and the central processorrespectively for receiving the radio signal to decode so as to obtainthe decoded audio signal and transmit the decoded audio signal to thecentral processor.
 8. The bug detector as claimed in claim 2, whereinthe central processor determines that whether the decoded audio signalis corresponding to the audio encoding signal or not; if true, then thecentral processor controls active quantity or brightness of the lightemitting diodes according to the intensity of the radio signal.